The man in his 70s from the Teesside area was driving a distinctive silver/grey Ford Transit camper van.
It collided with the roundabout near Wetherby Services, where junction 46 of the A1(M) joins the B1224, at around 10.40am today.
Police believe the driver had approached the roundabout from the A1(M) sliproad, travelling southbound.
Anyone who witnessed the collision, saw the vehicle in the moments leading up to it or has dashcam footage that may help the investigation should contact North Yorkshire Police on 101, select option 1 and quote incident number NYP28052020-0112.
You can also email Traffic Constable Dave Minto at email@example.com